Substituted isoxazoles are known having the formula ##EQU2## wherein R' and R" are aliphatic or aromatic hydrocarbon groups. Such isoxazoles are described, for example, in A. QUILICO, "CHEMISTRY OF HETEROCYCLIC COMPOUNDS", Vol. 17, page 1.
Some of the substituted isoxazoles have been synthesized by the reaction of hydroxylamine with a beta-diketone ##EQU3## such as by L. CLAISEN, BERICHTE 24 3900 (1891).
Corresponding intermediate 5-hydroxy-isoxazolines have not been synthesized in practice because the reactions leading to them are generally not arrested at that stage but proceed directly to produce the isoxazole, and they can not be isolated.